Method and apparatus for making foam-in-place cushions with selective distribution of foam

ABSTRACT

A method and apparatus for making a foam-in-place cushion in which a foam-forming composition is dispensed between two plastic film portions in a predetermined fashion to selectively control the distribution of the foam in the cushion. A foam dispenser can be moved in a transverse direction as foam is dispensed. A dispersion device can be employed to apply pressure on predetermined areas of the film portions towards each other so as to cause the composition to be redistributed in position in a predetermined manner while the composition is in a less than fully expanded state. The plastic film can then be sealed closed to form an expanding foam cushion that can be placed into a shipping carton where the cushion expands to fill void space, or into a mold where the cushion expands and is molded into a desired shape.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 11/411,708 filed on Apr. 26, 2006, now U.S. Pat. No. 7,607,911,the entire disclosure of which is hereby incorporated herein byreference.

BACKGROUND OF THE INVENTION

The present invention relates to a method and apparatus for makingfoam-in-place cushions having a foam-forming composition containedwithin a flexible bag formed from polymer film supplied as continuousweb material, the polymer film being sealed along longitudinal andtransverse seals to contain the foam-forming composition, and beingsevered to detach a foam-in-place cushion from the remaining webmaterial.

Foam-in-place packaging is a highly useful technique for on-demandprotection of packaged objects. In its most basic form, foam-in-placepackaging comprises injecting a foam-forming composition from adispenser into a container that holds an object to be cushioned.Typically, the object is wrapped in plastic to keep it from directcontact with the rising (expanding) foam. As the foam rises, it expandsinto the void space between the object and its container (e.g., acorrugated board box), thus forming a custom cushion for the object.

A common foam-forming composition is formed by mixing an isocyanatecompound with a hydroxyl-containing material, such as a polyol (i.e., acompound that contains multiple hydroxyl groups), typically in thepresence of water and a catalyst. The isocyanate and polyol precursorsreact to form polyurethane. At the same time, the water reacts with theisocyanate compound to produce carbon dioxide. The carbon dioxide causesthe polyurethane to expand into a foamed cellular structure, i.e., apolyurethane foam, which serves to protect the packaged object.

In other types of foam-in-place packaging, an automated apparatusproduces foam-in-place cushions by making bags from flexible plasticfilm and dispensing a foam-forming composition into the bags as they arebeing formed. As the composition expands into a foam within a bag, thebag is sealed shut and typically is then dropped into a containerholding the object to be cushioned. The rising foam again tends toexpand into the available space, but does so inside the bag. Because thebags are formed of flexible plastic, they form individual custom foamcushions around the packaged objects. Exemplary types of such packagingapparatus are assigned to the assignee of the present application, andare illustrated, for example, in U.S. Pat. Nos. 4,800,708, 4,854,109,5,027,583, 5,376,219, and 6,003,288, the contents of each of which areincorporated entirely herein by reference.

As will be noted from the patents listed above, the typical method offorming a foam-in-place cushion from a plastic bag is to heat-seal pliesof plastic film material together both transversely and longitudinallyas they are being fed from a stock supply to form a generallyrectangular bag with the foam inside. In some cases, the stock supply ofplastic film material can comprise a C-folded web so that one side ofthe bag is a fold rather than a heat seal. Foam-in-place packagingapparatus that operate in accordance with such methods have gained rapidand wide acceptance in the marketplace and have served their purposeswell.

However, improvement in the operation of such apparatus is continuallysought. In this regard, one difficulty associated with conventionallyproduced foam-in-place cushions is that the cushion as it is dischargedfrom the apparatus does not have the foam-forming composition evenlydistributed in the cushion. The foam-forming composition tends to bedispensed into the bottom of the bag and immediately begins expanding asthe precursor chemicals react. It is a common practice for an operatorto take the cushion discharged from the apparatus, lay the cushion on aflat surface, and use his or her hands to redistribute the foam-formingcomposition within the cushion into a layer of generally uniformthickness before the cushion is placed into a shipping container.

The problem with this technique is that by the time the operator is ableto get the cushion onto the flat surface, the foam-forming compositionhas already undergone a substantial degree of expansion. When thealready-formed foam is redistributed, the cellular structure of the foamis disturbed. This can cause the cushion to expand in volume by a lesseramount than it was designed to do, and therefore the foam density ishigher than desired. Moreover, the uniformity of the foam density may becompromised, such that substantial non-uniformities of density may becreated in the cushion. Consequently, the cushion may not have theprotective properties it was designed to have.

BRIEF SUMMARY OF THE INVENTION

The present invention addresses the above needs and achieves otheradvantages. In one embodiment of the invention, a method is provided formaking foam-in-place cushions, wherein a cushion-making cycle comprisesthe steps of:

-   -   providing a pair of continuous polymer film portions extending        along a longitudinal direction and positioning the film portions        in parallel opposing relation to each other;    -   positioning a foam dispenser between the film portions for        dispensing a foam-forming composition between the film portions,        the foam-forming composition being operable to react to form an        expanded polymer foam material, the dispenser being controllable        to be either in an “on” state wherein foam-forming composition        is dispensed from the dispenser or in an “off” state wherein        dispensing of the foam-forming composition is stopped; and    -   placing the foam-forming composition selectively between the        film portions by performing at least one of the following        operations: (1) moving the dispenser along a transverse        direction of the film portions as the foam-forming composition        is being dispensed; and (2) advancing the film portions in the        longitudinal direction through a dispersion device structured        and arranged to apply pressure on predetermined areas of the        film portions towards each other so as to cause the foam-forming        composition to be to be redistributed while the foam-forming        composition is in a less than fully expanded state.

The dispersion device can redistribute the foam-forming composition invarious ways for achieving various effects. In one embodiment, thedispersion device redistributes the composition into a layer ofsubstantially uniform thickness. In another embodiment, the dispersiondevice redistributes the composition into a layer whose thickness variesin a predetermined manner in at least one of the longitudinal andtransverse directions.

The redistribution or dispersion of the foam-forming composition by thedispersion device takes place immediately after the foam-formingcomposition is dispensed. Accordingly, the composition does not havetime to undergo any substantial degree of foaming, and hence theredistribution of the composition does not disturb the foam structurethat ultimately forms. The composition is able to expand by the desiredamount so that the cushion has the desired protective properties.

In yet another embodiment, the foam-forming composition is dispensed asa plurality of discrete volumes of foam-forming composition that arespaced apart in at least one of the longitudinal and transversedirections.

The invention also provides an apparatus for making foam-in-placecushions. The apparatus in accordance with one embodiment of theinvention comprises:

-   -   a film supply and guide system for supplying a pair of        continuous polymer film portions extending along a longitudinal        direction and for positioning the film portions in parallel        opposing relation to each other;    -   a dispenser disposed between the film portions and operable for        dispensing a foam-forming composition between the film portions,        the foam-forming composition being operable to react to form an        expanded polymer foam material;    -   a film drive mechanism structured and arranged for advancing the        film portions in the longitudinal direction; and    -   a dispersion device structured and arranged to apply pressure on        predetermined areas of the advancing film portions towards each        other so as to cause the foam-forming composition to be to be        redistributed while the foam-forming composition is in a less        than fully expanded state.

The dispersion device in accordance with one embodiment of the inventioncomprises first and second film-engaging members between which a gap isdefined through which the advancing film portions pass with thefoam-forming composition therebetween. A width of the gap is adjustableby moving the first and second film-engaging members relative to eachother.

In one embodiment, the first film-engaging member comprises a driveroller rotated by a drive motor about an axis parallel to the transversedirection, and the second film-engaging member comprises a dispersionmember extending along an axis parallel to and spaced from the axis ofthe drive roller, the drive roller contacting one of the film portionsand the dispersion member contacting the other film portion. Thedispersion member can be a freely rotatable roller, a driven roller, anon-rotating rod or bar, or the like. The film portions are advanced inthe longitudinal direction by the drive roller, which forms nips with apair of transversely spaced driven rollers, the opposite longitudinaledges of the film portions passing through the nips and beingfrictionally engaged and advanced by the drive roller.

The width of the gap between the drive roller and the dispersion membercan be set as a function of a characteristic of the cushion that it isdesired to produce. For example, the width can be set as a function ofthe volume of foam-forming composition dispensed. It is also possible tovary the width of the gap as the film portions are advanced through thegap. For instance, the gap can be made progressively wider as the filmportions are advanced in order to account for the expansion of thefoam-forming composition. As another example, the gap can be varied tocause predetermined variations in thickness of the layer of foam-formingcomposition along the longitudinal direction.

In one embodiment, the dispersion member is mounted in a frame that isrotatable about a pivot axis spaced from and parallel to the axis of thedispersion member, such that rotation of the frame about the pivot axiscauses the gap between the dispersion member and the drive roller tovary in width. According to one method aspect of the invention, at thebeginning of a cushion-making cycle the frame is initially positionedsuch that the dispersion member is in a first position closely adjacent(e.g., in nipping engagement with) the drive roller, and thefoam-forming composition is dispensed between the film portions upstreamof the dispersion member and drive roller. Next, the frame is rotated tomove the dispersion member to a second position spaced farther from thedrive roller to set the gap therebetween and the drive roller is rotatedto advance the film portions through the gap.

In accordance with one embodiment of the invention, the drive rolleradvances a predetermined length of the film portions through the gap andis then stopped to halt the film portions, and the film portions aresealed along a transverse seal and are severed. The sealing and severingsteps can be performed simultaneously by a heated member placed incontact with the film portions.

In one embodiment, a pressing member is mounted in the frame, and theframe is rotated about the pivot axis to cause the pressing member topress the film portions against the heated member in order to seal andsever the film portions.

At the beginning of a cushion-making cycle, a transverse seal of thefilm portions can be disposed downstream of the dispersion member anddrive roller, and the dispersion member can be placed in nippingengagement with the drive roller so as to press the film portionsagainst the drive roller. Accordingly, when the foam-forming compositionis dispensed between the film portions, the transverse seal is initiallyisolated from the foam-forming composition by the nipping engagementbetween the dispersion member and drive roller. The incidence ofrupturing of the transverse seal by forceful dispensing of thefoam-forming composition is thereby substantially reduced or eliminated.

The invention enables selective, controlled placement of foam in acushion by controlling variables such as movement of the foam dispenser,speed of dispenser movement, advancement of the film portions, speed offilm advancement, “on” and “off” operation of the dispenser, andoperation of the dispersion member for controlling foam thickness.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 is a perspective view of an apparatus for making foam-in-bagcushions in accordance with one embodiment of the invention;

FIG. 2 is a diagrammatic cross-sectional view through the apparatusalong a plane orthogonal to the axis of the supply roll of polymer film;

FIG. 3 is a front elevation of the apparatus showing details of themechanism for traversing the foam dispenser;

FIG. 4 is a diagrammatic illustration of a cushion showing one possiblepattern in which the foam-forming composition is dispensed in accordancewith one embodiment of the invention;

FIG. 5 a is a diagrammatic illustration of a cushion after passagethrough the dispersion device, in accordance with an embodiment of theinvention;

FIG. 5 b is a cross-sectional view through the cushion of FIG. 5 a;

FIG. 6 is a diagrammatic perspective view of a portion of an apparatusin accordance with another embodiment of the invention, having analternative film supply and drive system;

FIG. 7 is a top view of the film supply and drive system of theapparatus of FIG. 6;

FIG. 8 is a side view of the film supply and drive system;

FIG. 9 is a diagrammatic side view of the film drive system with thedispersion device and cross-sealing and cutoff device, showing afoam-forming composition being dispensed at the beginning of acushion-making cycle;

FIG. 10 is a view similar to FIG. 9, at a later instant in time at whichthe film drive system is operative to drive the film and the dispersiondevice has been actuated to set predetermined gap between the dispersiondevice and the drive roller to redistribute the foam-forming compositionbetween the film portions;

FIG. 11 is a view similar to FIGS. 9 and 10, at a still later instant intime at which the cross-sealing and cutoff device has been actuated toseal and cut off the cushion;

FIG. 12 is a front elevation of an apparatus having a pivoting foamdispenser in accordance with another embodiment of the invention,showing the foam dispenser in a first position;

FIG. 13 is a view similar to FIG. 12, showing the foam dispenser in asecond position;

FIG. 14 illustrates a dispersion roller having a non-constantcross-sectional shape along its length;

FIG. 15 is a diagrammatic plan view of a cushion formed using thedispersion roller of FIG. 14;

FIG. 16 is a cross-sectional view through the cushion of FIG. 15;

FIG. 17 illustrates a generally U-shaped structured formed by foldingthe cushion of FIG. 15;

FIG. 18 is a fragmentary perspective view of an apparatus having adriven dispersion roller in accordance with a further embodiment of theinvention; and

FIG. 19 is a fragmentary perspective view of the apparatus on anenlarged scale, showing details of the drive arrangement for driving thedispersion roller.

DETAILED DESCRIPTION OF THE INVENTION

The present inventions now will be described more fully hereinafter withreference to the accompanying drawings in which some but not allembodiments of the inventions are shown. Indeed, these inventions may beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will satisfy applicable legalrequirements. Like numbers refer to like elements throughout.

FIGS. 1 through 3 depict an apparatus 20 for making foam-in-bag cushionsin accordance with one embodiment of the invention. The apparatusincludes a pair of spaced-apart, parallel frame members 22, 24 each ofwhich is generally in the form of a plate, and a plurality of supportrods 26 or the like that are connected between the frame members 22, 24to form a generally rigid frame. At the top end of the frame, a pair offreely rotatable idler rollers 28, 30 are rotatably supported betweenthe frame members 22, 24 for supporting a supply roll 32 of two-ply filmmaterial. The supply roll comprises two separate polymer film plies laidone upon the other and then wound about a hollow tubular core to form aroll of the two-ply film material. As shown in FIG. 2, one ply 34 of thetwo-ply film material unwinds from the supply roll 32 and proceedsdownwardly past the idler roller 28; the ply 34 can be guided by two ofthe rods 26 as shown, or alternatively the upper rod 26 shown in FIG. 2can be omitted. The other ply 36 of the two-ply film material unwindsfrom the supply roll 32 and through a nip between the roll 32 and theother idler roller 30, and then proceeds downwardly and is guided byanother rod 26. An apparatus of generally the same type for makingfoam-in-bag cushions using a two-ply film supply is described in U.S.Pat. No. 6,178,725 and U.S. Pat. No. 6,472,638, the entire disclosuresof which are incorporated herein by reference.

The apparatus includes a drive roller 40 that is rotatably mountedbetween the frame members 22, 24 near a lower end of the frame and isdriven by a motor 42 mounted on the frame member 24. The apparatusfurther includes a pair of transversely spaced, freely rotating drivenrollers 44, 46 mounted on a shaft 48 that extends between the framemembers 22, 24. The driven rollers 44, 46 form nips with the driveroller 40. The film plies 34, 36 are threaded through the nips betweenthe driven rollers and the drive roller, as shown in FIG. 2. The driveroller 40 includes an outer surface that is resiliently compressible andfrictionally grips the film so that the film is driven by the driveroller substantially without slipping. For example, the drive roller canbe formed of a rigid cylindrical roller covered with a sleeve of foammaterial such as silicone foam having a durometer hardness of 70 Shore Aand having a thickness of about 0.25 inch. As illustrated, the drivenrollers 44, 46 can have circumferential ridges that are spaced apartalong the lengthwise direction of the rollers for imparting longitudinalridges in the edges of the film plies, which gives rigidity to the filmedges and also helps ensure that the film is driven straight out fromthe rollers and does not wrap around the drive roller 40.

The apparatus further comprises a foam dispenser 50 that is mounted on acarriage 52 disposed between the two film plies 34, 36. The carriage 52is slidably mounted on a guide rail 54 that extends between the framemembers 22, 24. A rotatable feed screw 56 is rotatably mounted betweenthe frame members and is driven by a reversible motor 57. The feed screwengages a nut (not shown) on the carriage 52. Thus, rotation of the feedscrew 56 in one direction causes the carriage 52 and dispenser 50 tomove to the left along guide rail 54 in FIG. 3, and rotation of the feedscrew in the opposite direction moves the carriage and dispenser to theright in FIG. 3. Variation in the rotational speed of the screw 56causes the speed of movement of the dispenser to be varied. The foamdispenser is fed by feed hoses 58, 60 that feed two precursor chemicalsto the dispenser, where the precursor chemicals mix (either internallywithin a mixing chamber of the dispenser, or externally upon beingdispensed from the dispenser), to form a foam-forming composition. Thecomposition is dispensed between the two plies 34, 36 of the polymerfilm material at a location just above (upstream of) the drive roller 40and driven rollers 44, 46.

By controlling the movement (i.e., positioning and, optionally, speed)of the dispenser 50 in the transverse direction it is possible todispense the foam-forming composition in any of various patterns. Thepossible patterns are further multiplied by driving the film plies 34,36 while the composition is being dispensed (and optionally varying thespeed of the film movement), and/or by momentarily interrupting the flowof the composition one or more times during the traversing of thedispenser 50 and/or during the movement of the film plies. FIG. 4 showsonly one of many possible patterns of the foam-forming composition 62that are possible in accordance with the invention. The illustratedzigzag pattern is formed by moving the dispenser back and forth suchthat the dispenser changes directions three times while the film plies34, 36 are driven by the drive roller 40. The pattern is continuous inthat the composition forms an unbroken string. However, discontinuouspatterns (not shown) formed by discrete spaced-apart regions ofcomposition are also possible by momentarily interrupting the flow ofthe composition, as noted. For instance, the foam can be dispensed astwo or more stripes extending transversely and spaced apartlongitudinally, as dots spaced apart transversely and longitudinally,etc.

An alternative embodiment of a film supply and drive system inaccordance with the invention is depicted in FIGS. 6 through 8. Thisembodiment employs a film supply roll 32′ of C-fold film, i.e., a flatfilm folded along a medial longitudinal line such that one edge of theflat film is aligned with the other edge of the flat film, thus formingtwo film portions 34′ and 36′ in parallel overlying relation. The supplyroll 32′ is mounted on a shaft 33 whose opposite ends protrude outbeyond the ends of the roll and engage slots 35 in the frame members22′, 24′ that are configured to cause the roll to engage the driveroller 40. The slots 35 are inclined such that gravity urges the supplyroll against the drive roller. Accordingly, rotation of the drive rollercauses the supply roll to be rotated so as to pay out the C-fold film.The film is guided upwardly and over a freely rotating guide roller 37rotatably mounted between the frame members 22′, 24′ and the two plies34′, 36′ are moved apart by a separator member 39 to make space for thedispenser that projects between the plies from the open edge of theC-fold film. The film is then threaded through the nips between thedrive roller 40 and the driven rollers 44, 46 as in the priorembodiment.

In the C-fold embodiment of the apparatus, as best seen in FIG. 7, theapparatus includes a longitudinal sealing device for sealing the twofilm plies 34′, 36′ together along the open edge of the C-fold filmafter the foam-forming composition has been dispensed between the plies.Various types of longitudinal sealing devices can be used, the inventionnot being limited in this respect. A suitable type of longitudinalsealing device is a sealing wire such as described in U.S. Pat. No.6,550,229, the entire disclosure of which is incorporated herein byreference. This type of sealing device comprises a sealing wire 64 thatwraps partially about the driven roller 44 and resides in a grooveformed in the roller (e.g., between two of the aforementionedcircumferential ridges of the roller) such that as the film plies passthrough the nip between the roller and the drive roller 40, the sealingwire contacts the film plies. The sealing wire comprises a resistancewire that becomes hot upon passing an electrical current through thewire, so as to heat the film plies to their melting point in thelocalized region contacted by the sealing wire, thereby sealing theplies together. Alternatively, the sealing device can be as described inU.S. Pat. No. 6,472,638, the entire disclosure of which is incorporatedherein by reference.

It will be recognized that in the first embodiment of the apparatusdescribed above employing a supply roll 32 of two-ply film, such alongitudinal sealing device is required at each of the two edges of thefilm. Accordingly, a sealing device as described above can be associatedwith the other driven roller 46.

The following description of a dispersion device and a cross-sealing andcutoff device is applicable to both of the above-described embodimentsof the invention. FIGS. 9 through 11 diagrammatically illustrate thestructure and operation of the dispersion device and the cross-sealingand cutoff device in accordance with one embodiment of the invention.The apparatus includes a dispersion member 70 that is movably mountedwith respect to the drive roller 40 and extends parallel to the driveroller's axis of rotation. In the illustrated embodiment, the dispersionmember 70 comprises a freely rotating roller that is rotatably mountedin a frame 72; however, alternatively the dispersion member can be anon-rotatable member such as a rod or the like, or can be a drivenroller that is rotatably driven by a suitable driving arrangement (notshown). The frame 72 itself is rotatably mounted in the apparatus suchthat it is rotatable about the axis of the shaft 48 of the drivenrollers 44, 46. A reversible motor 74 (FIG. 1) is coupled to the frame72 for rotating the frame either in one direction or the other. Rotationof the frame 72 about the axis of the shaft 48 causes the dispersionmember 70 to be moved toward or away from the drive roller 40. Anencoder (not shown) can be associated with the frame 72 (e.g., theencoder can be built into the motor 74) for allowing the rotationalorientation of the frame to be detected and to be controlled by suitablycontrolling the motor 74 based on the encoder output.

FIG. 9 depicts the frame 72 in a position placing the dispersion member70 in nipping engagement with the drive roller 40. Rotation of the frame72 in one direction is effective for moving the dispersion member awayfrom the drive roller so as to create a gap 74 therebetween, as shown inFIG. 10. Control of the positioning of the frame 72 is effective foradjusting the gap 74 to any of various distances depending on therequirements of the particular cushion being produced.

Because the frame 72 rotates about the axis of the driven rollers 44,46, the driven rollers remain in nipping engagement with the driveroller 40 regardless of the rotational positioning of the frame 72. Inaccordance with the invention, the frame 72 initially can be positionedas shown in FIG. 9, with the dispersion member 70 in nipping engagementwith the drive roller 40. The foam dispenser 50 is operated to dispensethe foam-forming composition 62 between the film plies 34, 36. The frame72 is rotated to move the dispersion member 70 away from the driveroller 40 to set a predetermined gap 74 and the drive roller 40 isrotated to drive the film through the apparatus as shown in FIG. 10. Thedispersion member 70 exerts pressure on the film portion 34 toward theopposite film portion 36 to cause the foam-forming composition 62 to bespatially redistributed between the film plies in a desired fashion asthe film is driven by the drive roller 40. This redistribution of thecomposition advantageously takes place before the composition hasundergone any significant degree of expansion.

The manner in which the composition is redistributed is dictated by thesize of the gap 74 and the configuration of the dispersion member 70, aswell as by whether the dispersion device rotates or is stationary. Forexample, FIGS. 5 a and 5 b show a cushion processed by a dispersionmember of constant circular cylindrical cross-section, wherein the sizeof the gap 74 is varied as the film is being driven through the gap.More particularly, the foam-forming composition is redistributed toinclude a region of relatively small thickness 76 produced by making thegap 74 smaller, flanked by two regions of greater thickness 78 producedby making the gap 74 larger. Thus, initially as the foam is dispensedand the film portions are advanced, the gap 74 is set larger to produceone of the thick regions 78, then the gap is reduced to produce the thinregion 76, and finally the gap is increased to produce the second thickregion 78. It is also possible to produce regions of differentthicknesses by configuring the dispersion device to have a non-constantshape for redistributing the foam composition in a non-constant fashionin the widthwise and/or lengthwise direction of the cushion. Theasymmetric shape of the regions 76, 78 as depicted in FIG. 5 a can beproduced by dispensing the foam in a generally C-shaped configuration bytraversing the dispenser back and forth as the film is advanced andpossibly varying the speed of the film. Alternatively, a generallysymmetric shape can be produced by keeping the dispenser stationary asthe foam is dispensed and the film is advanced.

Once the film plies have been driven for a length corresponding to thedesired length of the cushion to be produced, the drive roller 40 ishalted and the frame 72 is rotated as shown in FIG. 11 to cause asealing anvil 80 connected with the frame to urge the film plies againsta transverse sealing wire 82 that is heated by passing an electricalcurrent through the wire. The drive roller 40 forms a backing member forthe sealing wire 82 such that the anvil 80 can firmly urge the filmplies against the sealing wire. The anvil can have a surface that isresiliently deformable. For example, the anvil surface can be formed bya layer of polymer foam such as silicone foam of about 0.25 inchthickness. The heated sealing wire simultaneously severs the film pliesand also seals the plies together to form a transverse seal that sealsthe completed cushion along its top transverse edge and also serves tocreate the bottom transverse seal 83 (FIG. 9) for the next cushion to beproduced.

FIGS. 12 and 13 depict an apparatus in accordance with yet anotherembodiment of the invention, wherein parts of the apparatus have beenomitted for clarity. The apparatus differs from the previously describedembodiments in that the foam dispenser 150 is mounted on a traversingmechanism 160 that moves in a pivoting fashion rather than a linearlytranslating fashion. More specifically, the dispenser is mounted on thelower end of an arm 162 that pivots about an axis 164 located at anintermediate position along the length of the arm. The top end of thearm 162 is connected to a rod 166 of a fluid cylinder 168 such as apneumatic or hydraulic cylinder. Thus, retraction of the rod (FIG. 12)pivots the arm 162 in one direction and extension of the rod (FIG. 13)pivots the arm in the other direction. By suitably controlling thecylinder 168 as the foam composition is dispensed from the dispenser150, the foam composition can be dispensed in various patterns, aspreviously described.

The apparatus in accordance with any of the embodiments of the inventioncan include various sensors for detecting conditions in the apparatusand to aid in controlling the operation of the apparatus. For example,it may be desired to make a cushion of a predetermined length. Tocontrol the apparatus to make the desired cushion length, the filmsupply can have opaque bars B printed along the film at a known fixedinterval, as shown in FIG. 7. A photoelectric sensor (not shown) can belocated inside the machine housing and aimed to detect the bars. Thissensor can differentiate the bars from the unprinted film. Theelectronic control assembly (not shown) can count the bars based on theinformation received from the sensor and measure the length of film thathas advanced. In this way, the controller can accurately feed film inorder to make a cushion of the length desired. It can also sense whenthe film supply runs out and thus can stop the machine from attemptingto make a cushion without film.

Alternatively, the rotation of the drive roller 40 can be detected withan encoder or the like, and the encoder output can be used to determineprecisely how much film length has been driven through the apparatus.The encoder can be built into the motor 42 or can be separate from themotor. This allows the bars B to be eliminated from the film supply.

Upon power-up of the apparatus, the controller performs a cleaning cyclefor the dispenser's solvent system, and performs other self tests. Thesolvent system can be as described in U.S. Pat. No. 6,811,059 entitled“Self-Cleaning Fluid Dispenser”, the entire disclosure of which isincorporated herein by reference. Before the apparatus makes the firstcushion, it runs a cycle with film only and no chemical. This is toinsure that there is a bottom cross seal 83 (FIG. 9). The apparatusadvantageously produces an empty cushion each time it is powered up,whenever the film roll is changed, or after any error condition. Theoperator then selects a cushion length and thickness by pressing keys ona keypad connected with the controller. The length of the cushion can befrom a few inches to many feet, but most cushions will be in the rangeof 1 to 5 feet. The thickness is variable from about one-half inch toover 2 inches after the foam has expanded.

At the beginning of the cycle, the dispersion member 70 can be in thestarting position as shown in FIG. 9. The dispenser 50, 150 moves to apredetermined starting position and begins dispensing. The drive roller40 begins to drive the film, and the gap 74 between the dispersionmember 70 and drive roller is opened to the desired value as indicatedin FIG. 10. The drive roller advances the film the correct amount forthe length selected. During drive and dispensing, the dispenser can betraversed along the transverse direction (e.g., in a back and forthmotion), spreading a bead of foam inside the film plies at the junctionof the dispersion device and drive roller. Additionally, if desired, thedispersion member 70 can be moved to vary the size of the gap 74 as thefilm is advanced. The amount of chemical dispensed is determined by thecontroller based on the selected cushion length and thickness. While thefilm is advancing, the longitudinal sealing device(s) can be operated toseal the film plies together along the longitudinal edge(s). The sealingdevice(s) can be cycled off momentarily at one or more positions alongthe edge to create one or more spaces where the film is not fused, thusallowing air to vent from the bag as the foam expands. At the end of thedrive cycle the frame 72 is rotated into the cross-sealing and cutoffposition, and the cushion is sealed and severed as in FIG. 11. The frame72 is then rotated to a neutral position and the operator takes theexpanding cushion from the apparatus. At the end of the cycle, thedispenser is returned to a predetermined position and a solvent cycle isperformed to clean the dispenser.

The apparatus can also include a sensor for determining whether thedispenser nozzle is dirty and requires attention. Typically, when thedispenser nozzle is dirty, a foam build-up will form on the end of thenozzle and will protrude below the nozzle. The apparatus can include asensor such as a laser sensor positioned to direct a beam along a paththat will be clear as long as the nozzle does not have any significantfoam build-up, but that will be blocked when the foam builds up to acertain extent on the nozzle. The sensor can be directed toward areflector mounted in the apparatus, and the sensor and reflector can beplaced in a predetermined location, such as all the way to one side ofthe dispenser's range of travel, outside the path of the film throughthe apparatus. Accordingly, when the dispenser is placed in thepredetermined position, if the nozzle is not dirty the laser beam isreflected by the reflector back to a detector, which indicates a normalcondition of the nozzle. However, if the foam has built up far enough toblock the beam, the detector does not receive the beam and thusindicates the nozzle needs attention. Other types of sensors can be usedinstead of the laser and reflector arrangement.

In accordance with the invention, the dispersion of the foam-formingcomposition is controlled as the foam is dispensed between the pliesand/or immediately after dispensing. All manipulation of the foamplacement is completed while the chemical is in the liquid state andprior to any significant amount of expansion. Prior foam-in-bag machinesdispense the chemical into the center and bottom of the bag. An operatorwill often lay the bag on a table and spread the chemical by hand todisperse it across the bag so that the bag can fit into a limited space,such as between an object being packaged and the wall of a box. This isnot only time-consuming but is detrimental to the final condition of thecushion because the foam is not spread until it has substantiallyexpanded. Squeezing expanded foam removes gas bubbles and causes thefoam to become more dense, which changes the density and protectivecharacteristics that are designed into the foam cushion. Since thecushions of the present invention are immediately ready for use as theyemerge from the apparatus, they are less expanded and more pliable andcan be more conformably wrapped around the objects to be packaged,holding them more securely and providing increased protection. Since thedispersion of the foam-forming composition is completed prior toexpansion, the foam rises as designed, and the density is as designed.

Planar cushions formed in accordance with the invention can be used inmulti-layer packaging, which is especially useful when packing multiplesmall items. A cushion is laid flat and the items are arrayed onto it. Anext cushion is laid onto the top of the items and another layer ofitems is placed onto it, followed by another cushion, etc. In this way,multiple layers of items are sandwiched between cushions, which conformto the shape of the items to secure them.

Cushions made in accordance with the invention can also be used to linethe inside of a box or other container. An item can be placed into acontainer and then wrapped to hold it in place and protect it. Ifmultiple items are placed into a container, the cushion can be weavedthrough the items to hold them all in place.

The previous examples are applications unique to planar cushions andcannot be practically accomplished with foam-in-bag cushions made byprior machines because the cushions that emerge from such machines arenot planar but rather have the foam all located at the bottom of thebag, as already noted. The present invention, however, can also providedistinct advantages when used in traditional foam-in-bag applications.One such application is the packaging of fragile items in boxes forshipping. In general, a bag of expanding foam is placed in the bottom ofthe box. The item to be packed is placed on the expanding cushion.Another bag of expanding foam is then placed in the box on top of theitem and the box is sealed as the foam finishes expanding and curing.With other foam-in-bag cushions, all of the expanding foam is in thebottom of the bag as it is placed into the box. The packer will oftenspread the foam by hand to get better coverage and fill. The chemicalhas already risen substantially by the time it is spread. The action ofspreading partially expanded foam forces gas from the foam, so as itfinishes rising, the foam does not expand to its full extent. The foamis thus denser than it is designed to be, so its protective qualitieshave changed. Also, because the foam is denser, more chemical isrequired to fill the void. This increases the cost and decreases thequality of the packaging, and also increases shipping costs because ofthe greater weight of the cushions.

With the cushions of the present invention, all redistribution of thechemical is done before it has risen significantly, so the density iscorrect and less chemical is needed. This saves cost and produces abetter quality cushion. Another advantage is that, since the foam isspread more evenly across and around the object being packaged, it moreeasily and consistently fills the void space in the carton. The foam inthe present invention does not have to travel throughout the bag as itfills the void. This reduces pressures inside the box as the foamexpands since the foam does not have to force its way around the objectas it expands. Venting of the bag and complications caused by wrinklesin the film are thus less of an issue, and foam shrinkage caused by poorventing is virtually eliminated.

Another area in which the current invention has an advantage overexisting foam-in-bag products is in the molding of pre-formed cushions.The mold consists of a box with an internal cavity and a lid. Theinternal cavity is in the shape of the desired cushion. This cavitygenerally has a series of holes through it that connect to a plenum inthe back side of the mold, which is connected to a vacuum source. A bagof expanding foam is placed into the mold and the vacuum is applied toassist in sucking the bag of expanding foam into the depth and length ofthe cavity. As previously described, with traditional foam-in-bagproducts, all the foam is at one end of the bag, which means it is atone end of the mold. The mold lid is closed, and the expanding foam musttravel to the far end of the mold as it expands and fills. As the foamexpands and forces its way to the opposite end of the mold, internalpressures are created that exert large forces on the mold lid. Theseforces vary depending on the size and shape of the mold, but amedium-sized mold lid can easily see forces in excess of 50 pounds. Thevacuum remains on through most or all of the foam rise time to assistthe rising foam in filling the deepest parts of the cavity. Aspreviously mentioned, the foam may be spread by hand prior to placementinto the mold, but again, this densifies the foam and decreases yield.

With the current invention, the foam is spread prior to significantrising and can be tailored not only to the length and width of the mold,but also to the depth of the cavity. For example, the thickness of thefoam can be changed so that if, for instance, the cushion is to bethicker at the ends than in the middle, the chemical prior to expansioncan be made thicker at the ends then the middle, through suitable designand control of the dispersion device. When the bag is placed into themold, the chemical already covers the length and width of the cavity, sosubstantially all of the expansion of the foam occurs in the directionof the depth of the cavity. The internal pressures, and hence the forceson the lid, are greatly reduced. The example of the 50 pounds plusmentioned above may be on the order of 15 pounds with the currentinvention. Additionally, the vacuum needs to be on for only a shorttime, perhaps a second, since it is needed only to assist the bag insettling fully into the cavity. The cushions produced by this method areof a more consistent density and fill, and thus are of a higher qualitythan previous methods.

Furthermore, with prior foam-in-bag systems, the foam-formingcomposition is dispensed under a substantial amount of pressure directlyonto the lower seal of the bag. Any pinhole leaks or other weaknesses ofthe seal will cause the expanding chemical to leak to the outside of thefilm, where it can get onto the operator, the machine, and the itemsthat are being packaged with the cushion. However, the bottom seal canbe protected in accordance with the present invention by the nippingengagement between the dispersion member 70 and the drive roller 40,which isolates the bottom seal 83 from the foam composition asillustrated in FIG. 9. Additionally, the redistribution of the foamcomposition keeps the foam from expanding from only one point in thebag, and thus reduces forces on both the longitudinal and cross seals asthe foam expands.

With reference again to FIG. 1, in accordance with one embodiment of theinvention, the drive roller 40, the driven rollers 44, 46 on the shaft48, the dispersion member 70, the frame 72, the anvil 80 and thecross-sealing and cutoff wire 82 (not visible in FIG. 1), and the motors42 and 74 comprise a self-contained module that can be removed from theapparatus as a unit and replaced with another identical module or adifferently configured module. The module includes opposite framemembers 22 a, 24 a having support rods 26 connected therebetween. Themodule mounts in the apparatus by engaging thumb screws 84 of the modulein corresponding threaded holes of the frame members of the apparatus.The modularity of the design means that in a short time the module canbe replaced with one that uses a different width of film, or a modulehaving a dispersion member with a different shape. For example, thedispersion member can have troughs in it to shape the foam. A largerolling dispersion member can be used that has dimples or other shapesin it to create a foam version of bubble pack, a waffle shape, or manyothers. Instead of a rolling dispersion member, a variety of plow typedevices can be used to shape the foam.

FIG. 14 depicts a dispersion roller 170 having a non-constantcross-sectional shape along its length. In particular, the rollerincludes a first end portion 172, a middle portion 174, and a second endportion 176 all of which are circular cylindrical in shape and have afirst relatively small diameter. The roller further includes twolarger-diameter portions 178, one being disposed between the first endportion 172 and the middle portion 174, and the other being disposedbetween the middle portion 174 and the second end portion 176. Thelarger-diameter portions 178 are of circular cylindrical shape and havea second diameter larger than the first diameter of the portions 172,174, 176.

When a cushion containing a volume of foam-forming composition isadvanced through the gap between the dispersion roller 170 and the driveroller 40 (FIG. 10), the cushion 180 (FIGS. 15 and 16) is formed to havethree portions 182, 184, 186 of relatively larger thickness as formed bythe respective smaller-diameter portions 172, 174, 176 of the dispersionroller, and two portions 188 of smaller thickness as formed by thelarger-diameter portions 178 of the dispersion roller. Thesmaller-thickness portions are alternately arranged with thelarger-thickness portions. The smaller-thickness portions 188 can serveas hinges or fold lines to allow the cushion to be folded into agenerally U-shaped configuration as depicted in FIG. 17.

As noted, the dispersion member 70 can be a driven roller instead of afreely rotating roller. For instance, as illustrated in a furtherembodiment of the invention depicted in FIGS. 18 and 19, the dispersionroller 70 can be mechanically linked to the driven rollers 44, 46mounted on the shaft 48 such that the dispersion member is driven alongwith the driven rollers, and the mechanical linkage can be designed suchthat the dispersion member's peripheral speed has a predeterminedrelationship to the peripheral speed of the driven rollers 44, 46 (e.g.,the same as that of the driven rollers). As shown in FIG. 19, drivemembers 190 (e.g., belts or O-rings) or the like can be looped about ahub portion 192 of each of the driven rollers 44, 46 and aboutprojecting end portions 194 of the dispersion roller 70 such thatrotation of the driven rollers 44, 46 causes the dispersion roller toalso be rotated. The relative diameters of the hub portions 192 of therollers 44, 46 and the end portions 194 of the dispersion roller 70engaged by the drive members 190 can be selected such that the correctdrive ratio is provided in order to set the peripheral speed of thedispersion roller in a predetermined relationship to that of the drivenrollers (e.g., equal to or slightly faster than the driven rollers). Thedriven dispersion roller may be advantageous over a freely rotating onefor various reasons, including a lesser tendency for the film to bunchup in front of the dispersion roller.

As illustrated in FIG. 19, the driven roller 44 (and likewise theunillustrated roller 46) can include a recess in its end in which thehub portion 192, the drive member 190, and the dispersion roller endportion 194 reside. Additionally, as shown, the shaft 48 for the drivenrollers extends through apertures in support brackets 196 mounted onfixed structure of the apparatus. The support brackets are closelyadjacent the ends of the driven rollers having the recesses.

In light of the foregoing description of certain exemplary embodimentsof the invention, it will be appreciated that the present inventionenables expanding foam cushions to be produced with controlled placementof the foam within the polymer film. Such controlled placement isachieved through control of the position, speed of movement, andoperation of the foam dispenser 50, 150, control of the position of thedispersion member 70, and control of the film drive 40, 44, 46. Withrespect to the foam dispenser, the position of the dispenser can becontrolled as previously described, but additionally or alternativelythe dispenser can be controlled as to whether it is dispensing or notwhile the film is being advanced and/or while the dispenser is moving.For example, the dispenser can be moved and/or the film can be advancedwhile the dispenser is alternately turned on to dispense foam and turnedoff to stop dispensing foam, thereby creating discrete spaced-apart foamregions. The speed of the dispenser movement also can be varied whilethe dispenser is in its “on” state dispensing foam. With respect to thefilm drive, the speed of film advancement can be varied while thedispenser is “on” in order to help control the distribution of thefoam-forming composition. The invention thus enables substantialversatility through control over various primary variables affecting theplacement of foam.

As but one example of the versatility enabled by the invention, acushion can be produced having foam distributed in an elongatedgenerally C-shaped configuration to facilitate molding the cushion in amold having a C-shaped mold cavity wherein the two “legs” of the C-shapeand adjoining portions of the upright part of the C-shape extendingbetween the legs are relatively thick, and the middle portion of theupright part is relatively thin. In such a case, it is desirable for thefoam to be distributed in the cushion prior to molding such that thereis more foam composition where the thick portions are to be formed andless foam composition where the thin portion is to be formed.Accordingly, the following procedure can be used to produce the desiredcushion:

-   -   1) To start, the dispersion member 70 is closed (as in FIG. 9),        the dispenser 50, 150 is positioned in a location toward one        longitudinal edge of the film, and the film is driven for a        predetermined distance (e.g., 2 inches) while the dispenser is        “off”. This provides extra film at the bottom of the cushion to        create sufficient room for the foam to expand.    -   2) The dispenser is turned “on” and the dispenser is moved        toward the opposite longitudinal edge of the film for a        predetermined distance (e.g., 4 inches) and then brought to a        stop. The film is not driven during this movement of the        dispenser. This makes the lower leg of the C-shape.    -   3) The dispenser remains “on” and the film is driven a        predetermined distance (e.g., 6 inches) at a speed of 80% of        maximum. The slower speed allows more foam to be placed in the        cushion in this location. The dispersion member is moved to a        position that spreads the foam to a width approximately that of        the width of the molded cushion to be produced.    -   4) Through the middle of the upright of the C-shape, the molded        part has a thinner cross-section. The dispenser remains “on”,        and the film drive speed is increased to 90% so that relatively        less foam is dispensed in the middle portion. The gap between        the dispersion member and the drive roller is opened wider so as        not to spread the foam as much, because the molded part is        thinner as well as shallower in the middle portion of the        upright. This occurs for a predetermined distance (e.g., 18        inches) of film travel.    -   5) The film drive speed is reduced to 80% and the dispersion        roller is closed enough to spread the foam the width of the        molded part for the upper thick section, similar to step 3        above.    -   6) The film drive then stops and the dispenser (which is still        “on”) is moved toward the first longitudinal edge of the film        for a predetermined distance (e.g., 4 inches), similar to step 2        above, and the dispenser is shut off. This creates the upper leg        of the C-shape.    -   7) The dispersion member opens fully, the film is driven for a        predetermined distance (e.g., a few inches) and is then cut off.        The cushion is placed into the mold.

The above example is only one of a virtually unlimited variety ofprocesses that can be employed in accordance with the invention formaking cushions of many different configurations. With the ability toturn the dispenser on and off while moving the dispenser and/or the film(which ability is not employed in the above example), even more complexshapes can be created. The degree of control over the foam placementmade possible by the invention not only enables the cushion shape andits properties to be precisely controlled, but can also facilitate otheradvantages. For example, it is possible to eliminate or reduce the needfor sealing of the film portions by controlling the placement of thefoam in such a manner that even when fully expanded the foam remainsbetween the film portions without escaping. Thus, the longitudinaland/or the transverse seals potentially can be omitted, therebysimplifying the apparatus and process.

Many modifications and other embodiments of the inventions set forthherein will come to mind to one skilled in the art to which theseinventions pertain having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the inventions are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

1. An apparatus for making foam-in-place cushions, comprising: a filmsupply and guide system for supplying a pair of continuous polymer filmportions extending along a longitudinal direction and for positioningthe film portions in generally parallel opposing relation to each other;a dispenser disposed between the film portions and operable fordispensing a foam-forming composition between the film portions, thefoam-forming composition being operable to react to form an expandedpolymer foam material, the dispenser being controllable to be either inan “on” state wherein foam-forming composition is dispensed from thedispenser or in an “off” state wherein dispensing of the foam-formingcomposition is stopped; a film drive mechanism structured and arrangedfor advancing the film portions in the longitudinal direction; across-sealing and cutoff device operable to seal the film portionstogether and to sever the film portions along a transverse line; anautomated dispenser traversing mechanism operable to selectively movethe dispenser in a transverse direction relative to the film portionsduring dispensing of foam-forming composition or in between intermittentdispensing operations for a given cushion; and a dispersion devicestructured and arranged to apply pressure in a thickness direction on alocalized area of the film portions of a cushion being formed, during atime period in which the foam-forming composition for said cushion isbeing dispensed and prior to the cross-sealing and cutoff device'ssevering of the film portions, the dispersion device being adjustable inposition in the thickness direction relative to the film portions. 2.The apparatus of claim 1, wherein the dispersion device comprises adispersion member for applying pressure on the film portions and a motorcoupled to the dispersion member for adjusting the position of thedispersion member in the thickness direction.
 3. The apparatus of claim2, wherein the dispersion member is adjustable in position in thethickness direction during formation of a given cushion.